<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8" />
        <meta name="viewport" content="width=device-width, initial-scale=1.0" />
        <title>Document</title>
        <link
            rel="stylesheet"
            href="https://static.web.sdo.com/chuanshi/libs/common.css"
        />
        <style>
            ul {
                width: 400px;
                margin: 20px auto;
                display: flex;
                border: 2px solid red;
            }

            li {
                padding: 20px;
                width: 40px;
                height: 40px;
                line-height: 40px;
                text-align: center;
                color: #fff;
                background-color: brown;
                background-clip: content-box;
            }
        </style>
    </head>
    <body>
        <ul>
            <li>1</li>
            <li>2</li>
            <li>3</li>
        </ul>
    </body>
</html>
